One method of handling high data rate traffic (voice, computer or TV for example) is to have a communications ring (eg ORWELL) or a bus (eg a Distributed Queue Dual Bus DQDB) to provide a Local Area Network (LAN) or Wide Area Network (WAN) service. Such data is carried as packets through the network. With Asynchronous Transfer Mode (ATM) or DQDB configurations, the packets are designated as cells each of which can be considered to be made up of portions, for example 8-bit octets, for example a cell might be made up of 53, 8-bit octets.
One method of communicating a high data rate signal down several lower data rate paths is disclosed in PCT patent application WO 90/12467 published on 18th Oct. 1990, in which the differences in propagation time are compensated by transmitting a flag down each path, and by individually delaying the received signals in the receiver in response to the received flags, so that the broadband signal can be re-established from the portions by multiplexing.
Further, each flag is distinctive of each distinct path, so the receiver can identify the cyclic order of the paths from the flag information.
Standard ATM data formats, amongst other formats, for communication on a single high bandwidth path guarantees proper cell sequence order at a receiver. There is, therefore, no requirement for a mechanism identifying cells by any sequence identifier, for example a cell number, in standard ATM formats and so none is provided.
A disadvantage of above described multi-path communication method, if it were to be applied to present ATM communications standards, is that the flags would have to be added to the data stream, and their form and their content would need to be standardised if open communications are needed.